// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_VIEWS_CONTROLS_COMBOBOX_COMBOBOX_H_
#define UI_VIEWS_CONTROLS_COMBOBOX_COMBOBOX_H_

#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/strings/string16.h"
#include "base/time/time.h"
#include "ui/views/controls/button/button.h"
#include "ui/views/controls/prefix_delegate.h"

namespace gfx {
class FontList;
}

namespace ui {
class ComboboxModel;
class MenuModel;
}

namespace views {
namespace test {
    class ComboboxTestApi;
}

class ComboboxListener;
class CustomButton;
class MenuRunner;
class Painter;
class PrefixSelector;

// A non-editable combobox (aka a drop-down list or selector).
// Combobox has two distinct parts, the drop down arrow and the text. Combobox
// offers two distinct behaviors:
// * STYLE_NORMAL: typical combobox, clicking on the text and/or button shows
// the drop down, arrow keys change selection, selected index can be changed by
// the user to something other than the first item.
// * STYLE_ACTION: clicking on the text notifies the listener. The menu can be
// shown only by clicking on the arrow. The selected index is always reverted to
// 0 after the listener is notified.
class VIEWS_EXPORT Combobox : public PrefixDelegate, public ButtonListener {
public:
    // The style of the combobox.
    enum Style {
        STYLE_NORMAL,
        STYLE_ACTION,
    };

    // The combobox's class name.
    static const char kViewClassName[];

    // |model| is not owned by the combobox.
    explicit Combobox(ui::ComboboxModel* model);
    ~Combobox() override;

    static const gfx::FontList& GetFontList();

    // Sets the listener which will be called when a selection has been made.
    void set_listener(ComboboxListener* listener) { listener_ = listener; }

    void SetStyle(Style style);

    // Informs the combobox that its model changed.
    void ModelChanged();

    // Gets/Sets the selected index.
    int selected_index() const { return selected_index_; }
    void SetSelectedIndex(int index);

    // Looks for the first occurrence of |value| in |model()|. If found, selects
    // the found index and returns true. Otherwise simply noops and returns false.
    bool SelectValue(const base::string16& value);

    ui::ComboboxModel* model() const { return model_; }

    // Set the accessible name of the combobox.
    void SetAccessibleName(const base::string16& name);

    // Visually marks the combobox as having an invalid value selected.
    // When invalid, it paints with white text on a red background.
    // Callers are responsible for restoring validity with selection changes.
    void SetInvalid(bool invalid);
    bool invalid() const { return invalid_; }

    // Overridden from View:
    gfx::Size GetPreferredSize() const override;
    const char* GetClassName() const override;
    bool SkipDefaultKeyEventProcessing(const ui::KeyEvent& e) override;
    bool OnKeyPressed(const ui::KeyEvent& e) override;
    bool OnKeyReleased(const ui::KeyEvent& e) override;
    void OnPaint(gfx::Canvas* canvas) override;
    void OnFocus() override;
    void OnBlur() override;
    void GetAccessibleState(ui::AXViewState* state) override;
    void Layout() override;

    // Overridden from PrefixDelegate:
    int GetRowCount() override;
    int GetSelectedRow() override;
    void SetSelectedRow(int row) override;
    base::string16 GetTextForRow(int row) override;

    // Overriden from ButtonListener:
    void ButtonPressed(Button* sender, const ui::Event& event) override;

private:
    friend class test::ComboboxTestApi;

    class ComboboxMenuModelAdapter;

    // Updates the border according to the current state.
    void UpdateBorder();

    // Given bounds within our View, this helper mirrors the bounds if necessary.
    void AdjustBoundsForRTLUI(gfx::Rect* rect) const;

    // Draws the selected value of the drop down list
    void PaintText(gfx::Canvas* canvas);

    // Draws the button images.
    void PaintButtons(gfx::Canvas* canvas);

    // Show the drop down list
    void ShowDropDownMenu(ui::MenuSourceType source_type);

    // Called when the selection is changed by the user.
    void OnPerformAction();

    int GetDisclosureArrowLeftPadding() const;
    int GetDisclosureArrowRightPadding() const;

    // Returns the size of the disclosure arrow.
    gfx::Size ArrowSize() const;

    // Finds the size of the largest menu label or, for STYLE_ACTION, the size of
    // the selected label.
    gfx::Size GetContentSize() const;

    // Handles the clicking event.
    void HandleClickEvent();

    PrefixSelector* GetPrefixSelector();

    // Our model. Not owned.
    ui::ComboboxModel* model_;

    // The visual style of this combobox.
    Style style_;

    // Our listener. Not owned. Notified when the selected index change.
    ComboboxListener* listener_;

    // The current selected index; -1 and means no selection.
    int selected_index_;

    // True when the selection is visually denoted as invalid.
    bool invalid_;

    // The accessible name of this combobox.
    base::string16 accessible_name_;

    // A helper used to select entries by keyboard input.
    scoped_ptr<PrefixSelector> selector_;

    // Adapts a ComboboxModel for use by a views MenuRunner.
    scoped_ptr<ui::MenuModel> menu_model_adapter_;

    // Like MenuButton, we use a time object in order to keep track of when the
    // combobox was closed. The time is used for simulating menu behavior; that
    // is, if the menu is shown and the button is pressed, we need to close the
    // menu. There is no clean way to get the second click event because the
    // menu is displayed using a modal loop and, unlike regular menus in Windows,
    // the button is not part of the displayed menu.
    base::Time closed_time_;

    // The maximum dimensions of the content in the dropdown.
    gfx::Size content_size_;

    // The painters or images that are used when |style_| is STYLE_BUTTONS. The
    // first index means the state of unfocused or focused.
    // The images are owned by ResourceBundle.
    scoped_ptr<Painter> body_button_painters_[2][Button::STATE_COUNT];
    std::vector<const gfx::ImageSkia*>
        menu_button_images_[2][Button::STATE_COUNT];

    // The transparent buttons to handle events and render buttons. These are
    // placed on top of this combobox as child views, accept event and manage the
    // button states. These are not rendered but when |style_| is
    // STYLE_NOTIFY_ON_CLICK, a Combobox renders the button images according to
    // these button states.
    // The base View takes the ownerships of these as child views.
    CustomButton* text_button_;
    CustomButton* arrow_button_;

    // Set while the dropdown is showing. Ensures the menu is closed if |this| is
    // destroyed.
    scoped_ptr<views::MenuRunner> menu_runner_;

    // Used for making calbacks.
    base::WeakPtrFactory<Combobox> weak_ptr_factory_;

    DISALLOW_COPY_AND_ASSIGN(Combobox);
};

} // namespace views

#endif // UI_VIEWS_CONTROLS_COMBOBOX_COMBOBOX_H_
